Elastic materials, especially elastic films, are commonly used for a wide variety of applications. For example, disposable absorbent articles typically include one or more components that rely on film materials, especially elastic film materials, to control the movement of liquids and to provide a comfortable, conforming fit when the article is worn by a wearer. However, conventional elastic film materials have been known to at least partially tear when subjected to the normal wear and tear on the article when in use. Such tearing may be related to, for example, material defects, contact with sharp objects, pulling and stretching by a wearer, rigorous activity of a wearer, and/or repetitive mechanical stress experienced during wear and/or manufacture. Additionally, it is not uncommon for film materials to be subjected to vigorous mechanical and/or thermal stress during various manufacturing processes (e.g., incremental stretching processes or bonding processes such as high pressure bonding, thermal bonding, and ultrasonic bonding), which may result in undesirable tears and/or holes in the film. In some instances, it may even be desirable to intentionally include one or more pre-formed discontinuities (e.g., one or more apertures) that extend at least partially through the thickness of the film, for example, to control the breathability, permeability to liquids and/or solids, opacity, and/or extensibility of the article or article component that includes the film.
Initially, openings in the film, whether desired or undesired, may start out small and be relatively inconsequential with regard to the desired function of the film, article component and/or article. But as the size of the opening grows, it may ultimately lead to partial or complete (catastrophic) failure of the film, article component and/or article. Unintended catastrophic failure of an article or article component is almost always undesirable, but when the article is a disposable absorbent article such as a diaper or training pant, the consequences of catastrophic failure of the article or component may be especially acute due to, for example, the possibility of bodily exudates escaping from the article and/or the article becoming separated from the wearer. To further compound the potential problems associated with conventional films, at least some manufacturers desire to use thinner and/or lower basis weight films to reduce material costs. The aforementioned problems associated with the formation of tears, holes, and apertures in a film may be even more acute in thinner/lower basis weight films.
In order to reduce the possibility that the elastic film incorporated into an article will fail due to the presence and/or formation of a hole, tear, and/or aperture, the strength of the film may be increased. Increasing the strength of the film typically means increasing the thickness of the film or forming the film from different materials, both of which may undesirably impact the cost and/or complexity of manufacturing the film or the suitability of the film for a particular use. For example, using a stronger film in an absorbent article such as a diaper or pant may result in an undesirable amount of pressure being applied to the skin of a wearer, which may lead to red-marking and/or discomfort. Additionally, increasing the overall strength of the film may only improve the film's resistance to the initial formation of a hole, tear, or aperture and not its subsequent growth.
Another method for reducing the possibility of undesired growth of a tear, hole, and/or aperture in a film, especially in a low basis weight film, includes joining one or more reinforcing layers to the film. For example, the film may be sandwiched between two or more nonwoven layers and/or the film may be formed with one or more commonly known “skin layers” (e.g., through a co-extrusion process). However, adding additional layers of material to improve the performance of the film may undesirably increase the cost and/or complexity of producing a particular article or article component that incorporates the film and/or make the film unsuitable for its intended purpose. Thus, there remains a need to provide a film suitable for use in an absorbent article that exhibits resistance to the growth of tears, holes, and/or apertures in a variety of circumstances (e.g., at a low basis weight) without the use of additional reinforcing materials.
Accordingly, it would be desirable to provide a film that has an improved resistance to the growth of a tear, hole, or aperture.